The motion equations of matter in a gravitational field, acceleration field, pressure field, and other fields are considered based on the field theory. This enables us to derive simple formulas in the framework of the gravitational equilibrium model, which allow us to estimate the physical parameters of cosmic bodies. The acceleration field coefficient, η, and the pressure field coefficient, σ, are a function of the state of matter, and their sum is close in magnitude to the gravitational constant, G. In the presented model the dependence is found of the internal temperature and pressure on the current radius. The central temperatures and pressures are calculated for the Earth and the Sun, for a typical neutron star and a white dwarf. The heat flux and the thermal conductivity coefficient of these objects’ matter are found, and the formula for estimating the entropy is provided. All the quantities are compared with the calculation results in different models of cosmic bodies. The discovered good agreement with these data proves the effectiveness and universality of the proposed model for estimating the parameters of planets and stars and for more precise calculation of physical quantities.